(function () {
  function w () {
    var r = document.documentElement
    var a = r.getBoundingClientRect().width
    if (a > 750) {
      a = 750
    }
        // 750/w = 100/font-size
    rem = a / 7.5
    r.style.fontSize = rem + 'px'
  }
  var t
  w()
  window.addEventListener('resize', function () {
    clearTimeout(t)
    t = setTimeout(w, 300)
  }, false)
})()
